Location based notification in ionic


In my ionic project, i want a feature to show notification when a place reached. I used geofence to make it. but, when i was in that place the notification showing repeatedly. futures: 1.if i install the app,when i reached the position(already added),the notification must come.(background checking)

Observable.interval(100 * 60).subscribe(x => {

 private addGeofence() {
    //options describing geofence
    let fence = {
      id: '69ca1b88-6fbe-4e80-a4d4-faizy4d3748acdb', //any unique ID
      latitude:       8.556498, //center of geofence radius
      longitude:      76.881820,
      radius:         100, //radius to edge of geofence in meters
      transitionType: 1, //see 'Transition Types' below
      notification: { //notification settings
        id:             121212122, //any unique ID
        title:          'You crossed a fence', //notification title
        text:           'You just arrived to white oval technology.', //notification body
        openAppOnClick: true //open app when notification is tapped